2.2.0.7 true Document and Entity Information 101 - Document - Document and Entity Information true false false false 1 false false shares Standard http://www.xbrl.org/2003/instance shares 0 iso4217_USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 iso4217_USD_per_shares Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 2 Document Type 2 dei_DocumentType dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 10-Q false false false us-types:SECReportItemType na The type of document being provided (such as 10-K, 10-Q, N-1A, etc). The document type should be limited to the same value as the supporting SEC submission type. The acceptable values are as follows: S-1, S-3, S-4, S-11, F-1, F-3, F-4, F-9, F-10, 6-K, 8-K, 10, 10-K, 10-Q, 20-F, 40-F, N-1A, 485BPOS, NCSR, N-Q, and Other. No authoritative reference available. false 3 Amendment Flag 2 dei_AmendmentFlag dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false false xbrli:booleanItemType na If the value is true, then the document as an amendment to previously-filed/accepted document. No authoritative reference available. false 4 Document Period End Date 2 dei_DocumentPeriodEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 2010-09-30 false false false xbrli:dateItemType date The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements this will be the filing date. The format of the date is CCYY-MM-DD. No authoritative reference available. false 5 Document Fiscal Year Focus 2 dei_DocumentFiscalYearFocus dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 2010 false false false xbrli:gYearItemType positiveinteger This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006. No authoritative reference available. false 6 Document Fiscal Period Focus 2 dei_DocumentFiscalPeriodFocus dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Q3 false false false us-types:fiscalPeriodItemType na This is focus fiscal period of the document report. For a first quarter 2006 quarterly report, which may also provide financial information from prior periods, the first fiscal quarter should be given as the fiscal period focus. Values: FY, Q1, Q2, Q3, Q4, H1, H2, M9, T1, T2, T3, M8, CY. No authoritative reference available. false 8 Entity Registrant Name 2 dei_EntityRegistrantName dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 PEPCO HOLDINGS INC false false false xbrli:normalizedStringItemType normalizedstring The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 9 Entity Central Index Key 2 dei_EntityCentralIndexKey dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 0001135971 false false false us-types:centralIndexKeyItemType na A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 10 Current Fiscal Year End Date 2 dei_CurrentFiscalYearEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 --12-31 false false false xbrli:gMonthDayItemType monthday End date of current fiscal year in the format --MM-DD. No authoritative reference available. false 11 Entity Filer Category 2 dei_EntityFilerCategory dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Large Accelerated Filer false false false us-types:filerCategoryItemType na Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, or (4) Smaller Reporting Company. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 12 Entity Common Stock, Shares Outstanding 2 dei_EntityCommonStockSharesOutstanding dei false na instant No definition available. false false false false false false false false false false false false 1 false true false false 224500318 224500318 false false false xbrli:sharesItemType shares Indicate number of shares outstanding of each of registrant's classes of common stock, as of latest practicable date. Where multiple classes exist define each class by adding class of stock items such as Common Class A [Member], Common Class B [Member] onto the Instrument [Domain] of the Entity Listings, Instrument No authoritative reference available. false 13 PEPCO HOLDINGS INC 0 na true na na No definition available. false true false false false false false false false false false http://www.pepcoholdings.com/taxonomy/role/documentdocumentandentityinformation false 1 false false false false 0 0 false false false false 2 USD true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember iso4217_USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 iso4217_USD_per_shares Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 shares Standard http://www.xbrl.org/2003/instance shares 0 $ na No definition available. No authoritative reference available. false 19 Trading Symbol 2 dei_TradingSymbol dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 POM false false false xbrli:normalizedStringItemType normalizedstring Trading symbol of an instrument as listed on an exchange. No authoritative reference available. false 25 ATLANTIC CITY ELECTRIC CO 0 na true na na No definition available. false true false false false false false false false false false http://www.pepcoholdings.com/taxonomy/role/documentdocumentandentityinformation false 1 false false false false 0 0 false false false false 3 USD true false false false ATLANTIC CITY ELECTRIC CO dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi pom_AtlanticCityElectricCoMember dei_LegalEntityAxis explicitMember iso4217_USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 shares Standard http://www.xbrl.org/2003/instance shares 0 iso4217_USD_per_shares Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 $ na No definition available. No authoritative reference available. false 32 Entity Registrant Name 2 dei_EntityRegistrantName dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 ATLANTIC CITY ELECTRIC CO false false false xbrli:normalizedStringItemType normalizedstring The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 33 Entity Central Index Key 2 dei_EntityCentralIndexKey dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 0000008192 false false false us-types:centralIndexKeyItemType na A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 34 Current Fiscal Year End Date 2 dei_CurrentFiscalYearEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 --12-31 false false false xbrli:gMonthDayItemType monthday End date of current fiscal year in the format --MM-DD. No authoritative reference available. false 35 Entity Filer Category 2 dei_EntityFilerCategory dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Non-accelerated Filer false false false us-types:filerCategoryItemType na Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, or (4) Smaller Reporting Company. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 36 Entity Common Stock, Shares Outstanding 2 dei_EntityCommonStockSharesOutstanding dei false na instant No definition available. false false false false false false false false false false false false 1 false true false false 8546017 8546017 false false false xbrli:sharesItemType shares Indicate number of shares outstanding of each of registrant's classes of common stock, as of latest practicable date. Where multiple classes exist define each class by adding class of stock items such as Common Class A [Member], Common Class B [Member] onto the Instrument [Domain] of the Entity Listings, Instrument No authoritative reference available. false 37 DELMARVA POWER & LIGHT CO /DE/ 0 na true na na No definition available. false true false false false false false false false false false http://www.pepcoholdings.com/taxonomy/role/documentdocumentandentityinformation false 1 false false false false 0 0 false false false false 4 USD true false false false DELMARVA POWER & LIGHT CO /DE/ dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi pom_DelmarvaPowerLightCoMember dei_LegalEntityAxis explicitMember iso4217_USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 shares Standard http://www.xbrl.org/2003/instance shares 0 iso4217_USD_per_shares Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 $ na No definition available. No authoritative reference available. false 44 Entity Registrant Name 2 dei_EntityRegistrantName dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 DELMARVA POWER & LIGHT CO /DE/ false false false xbrli:normalizedStringItemType normalizedstring The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 45 Entity Central Index Key 2 dei_EntityCentralIndexKey dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 0000027879 false false false us-types:centralIndexKeyItemType na A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 46 Current Fiscal Year End Date 2 dei_CurrentFiscalYearEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 --12-31 false false false xbrli:gMonthDayItemType monthday End date of current fiscal year in the format --MM-DD. No authoritative reference available. false 47 Entity Filer Category 2 dei_EntityFilerCategory dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Non-accelerated Filer false false false us-types:filerCategoryItemType na Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, or (4) Smaller Reporting Company. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 48 Entity Common Stock, Shares Outstanding 2 dei_EntityCommonStockSharesOutstanding dei false na instant No definition available. false false false false false false false false false false false false 1 false true false false 1000 1000 false false false xbrli:sharesItemType shares Indicate number of shares outstanding of each of registrant's classes of common stock, as of latest practicable date. Where multiple classes exist define each class by adding class of stock items such as Common Class A [Member], Common Class B [Member] onto the Instrument [Domain] of the Entity Listings, Instrument No authoritative reference available. false 49 POTOMAC ELECTRIC POWER CO 0 na true na na No definition available. false true false false false false false false false false false http://www.pepcoholdings.com/taxonomy/role/documentdocumentandentityinformation false 1 false false false false 0 0 false false false false 5 USD true false false false POTOMAC ELECTRIC POWER CO dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi pom_PotomacElectricPowerCoMember dei_LegalEntityAxis explicitMember iso4217_USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 shares Standard http://www.xbrl.org/2003/instance shares 0 iso4217_USD_per_shares Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 $ na No definition available. No authoritative reference available. false 56 Entity Registrant Name 2 dei_EntityRegistrantName dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 POTOMAC ELECTRIC POWER CO false false false xbrli:normalizedStringItemType normalizedstring The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 57 Entity Central Index Key 2 dei_EntityCentralIndexKey dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 0000079732 false false false us-types:centralIndexKeyItemType na A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 58 Current Fiscal Year End Date 2 dei_CurrentFiscalYearEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 --12-31 false false false xbrli:gMonthDayItemType monthday End date of current fiscal year in the format --MM-DD. No authoritative reference available. false 59 Entity Filer Category 2 dei_EntityFilerCategory dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Non-accelerated Filer false false false us-types:filerCategoryItemType na Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, or (4) Smaller Reporting Company. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 60 Entity Common Stock, Shares Outstanding 2 dei_EntityCommonStockSharesOutstanding dei false na instant No definition available. false false false false false false false false false false false false 1 false true false false 100 100 false false false xbrli:sharesItemType shares Indicate number of shares outstanding of each of registrant's classes of common stock, as of latest practicable date. Where multiple classes exist define each class by adding class of stock items such as Common Class A [Member], Common Class B [Member] onto the Instrument [Domain] of the Entity Listings, Instrument No authoritative reference available. false 1 30 false UnKnown NoRounding UnKnown false true